Mr. Ban, who has repeatedly called climate change and its attendant consequences of increased droughts, floods, rising seas and more violent storms “the defining challenge of our era,” will urge the leaders of the 53-member Commonwealth to attend the summit, confident that strong momentum is building for a framework that can be moulded into a legally binding climate treaty as early as possible in 2010. Yesterday he welcomed the announcement that United States President Barack Obama will go to Copenhagen as yet another sign of the gathering momentum. Over the next two days in Port of Spain, Mr. Ban will urge the Commonwealth leaders to stay focused and committed to reach an agreement “that is ambitious, equitable, and satisfies the demands of science,” spokesperson Farhan Haq told a news briefing in New York yesterday.“The world cannot afford to fail in Copenhagen because the costs are simply too great, the Secretary-General will urge the leaders. Failure to seal a deal could result in increased human suffering, higher economic losses, opportunities squandered in terms of productivity, global competitiveness and political stability,” Mr. Haq added.For more than a year, Mr. Ban has let barely a speech go by without calling on world leaders to face up to the challenge of forging a successor to the 1997 Kyoto Protocol, which set limits on global warming greenhouse gases for industrialized nations and whose first commitment period expires in 2012. The Executive Secretary of the UN Framework Convention on Climate Change (UNFCCC), Yvo de Boer, told reporters last week that President Obama’s presence in the Danish capital “would make a huge difference.”He added today that the US commitment to specific, mid-term emission cut targets and China’s commitment to specific action on energy efficiency can “unlock two of the last doors” to a comprehensive agreement. “Let there be no doubt that we need continued strong ambition and leadership,” he stated. “In particular, we still await clarity from industrialised nations on the provision of large-scale finance to developing countries for immediate and long-term climate action.”In addition to commitments on financing, Mr. de Boer has cited individualized targets “in black and white” by industrialized States to reduce greenhouse gas emissions by 2020, and a list of actions by developing nations, as the main points that must come out of Copenhagen.Originally it had been hoped to produce the legally binding treaty in Copenhagen but persistent differences in pre-summit talks on these issues pushed back the timeframe and Mr. de Boer now hopes a formal treaty will follow within six months. 26 November 2009On the final lap of the years-long marathon to the United Nations climate change summit in Copenhagen next month, Secretary-General Ban Ki-moon takes his call for urgent action to a meeting of Commonwealth leaders in Trinidad and Tobago on Friday, the last global gathering before the summit.